scholarly journals Developing a novel approach to analyse the regimes of temporary streams and their controls on aquatic biota

2011 ◽  
Vol 8 (5) ◽  
pp. 9637-9673 ◽  
Author(s):  
F. Gallart ◽  
N. Prat ◽  
E. M. García-Roger ◽  
J. Latron ◽  
M. Rieradevall ◽  
...  

Abstract. Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. The use of the aquatic fauna structural and functional characteristics to assess the ecological quality of a temporary stream reach can not therefore be made without taking into account the controls imposed by the hydrological regime. This paper develops some methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: flood, riffles, connected, pools, dry and arid. We used the water discharge records from gauging stations or simulations using rainfall-runoff models to infer the temporal patterns of occurrence of these states using the developed aquatic states frequency graph. The visual analysis of this graph is complemented by the development of two metrics based on the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of the aquatic regimes of temporary streams in terms of their influence over the development of aquatic life is put forward, defining Permanent, Temporary-pools, Temporary-dry and Episodic regime types. All these methods were tested with data from eight temporary streams around the Mediterranean from MIRAGE project and its application was a precondition to assess the ecological quality of these streams using the current methods prescribed in the European Water Framework Directive for macroinvertebrate communities.

2012 ◽  
Vol 16 (9) ◽  
pp. 3165-3182 ◽  
Author(s):  
F. Gallart ◽  
N. Prat ◽  
E. M. García-Roger ◽  
J. Latron ◽  
M. Rieradevall ◽  
...  

Abstract. Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The structure and composition of biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. Therefore, the structural and functional characteristics of aquatic fauna to assess the ecological quality of a temporary stream reach cannot be used without taking into account the controls imposed by the hydrological regime. This paper develops methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the transient sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: Hyperrheic, Eurheic, Oligorheic, Arheic, Hyporheic and Edaphic. When the hydrological conditions lead to a change in the aquatic state, the structure and composition of the aquatic community changes according to the new set of available habitats. We used the water discharge records from gauging stations or simulations with rainfall-runoff models to infer the temporal patterns of occurrence of these states in the Aquatic States Frequency Graph we developed. The visual analysis of this graph is complemented by the development of two metrics which describe the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of temporary streams in four aquatic regimes in terms of their influence over the development of aquatic life is updated from the existing classifications, with stream aquatic regimes defined as Permanent, Temporary-pools, Temporary-dry and Episodic. While aquatic regimes describe the long-term overall variability of the hydrological conditions of the river section and have been used for many years by hydrologists and ecologists, aquatic states describe the availability of mesohabitats in given periods that determine the presence of different biotic assemblages. This novel concept links hydrological and ecological conditions in a unique way. All these methods were implemented with data from eight temporary streams around the Mediterranean within the MIRAGE project. Their application was a precondition to assessing the ecological quality of these streams.


2021 ◽  
Author(s):  
Francesc Gallart ◽  
Núria Cid ◽  
Pilar Llorens ◽  
Jérôme Latron ◽  
Núria Bonada ◽  
...  

<p>Water courses that recurrently cease to flow represent a large part of drainage networks, and are expected to expand with global warming and increased exploitation of water resources. Common classifications of the regime of these temporary streams are based on the statistics of zero flow events. This is partly practical because these statistics can be obtained from flow records or model simulations and the results can be used for some environmental regulations or management purposes.</p><p>Nevertheless, it is well known that the main hydrological control on riverine aquatic life is the presence-absence of water rather than its flow regime. Disconnected pools that frequently remain in temporary streams after flow cessation provide valuable refuges for aquatic life, which can last up to all year round. An operational characterisation of the hydrological regime of temporary streams useful for ecological purposes must therefore take into account at least the three main aquatic phases that they undergo: flow, disconnected pools and dry stream bed. However, gauging stations and the derived hydrological models may only marginally inform about the possible occurrence of disconnected pools after the cessation of flow.</p><p>In order to facilitate the implementation of the European Water Framework Directive to the temporary streams, an operational approach has been developed to describe and classify the regime of temporary streams and to assess their degree of hydrologic alteration, relevant to aquatic life. This approach is encapsulated in the freely available TREHS software. The first step of this approach is the gathering of information on the frequency of the three aquatic phases using diverse sources of information, such as flow records and simulations, <em>in situ</em> observations, interpretation of aerial or terrestrial series of photographs, and interviews with local inhabitants or technicians familiar with the riverine systems. Up to six metrics describing these frequencies and their temporal patterns of occurrence are used to determine the natural and observed stream regime, and to assess the degree of hydrological alteration.</p><p>The combination of the complementary frequencies of the three main aquatic phases allows the description of the regime of every stream as a point in a ternary plot, where the three vertices of the triangle represent the perennial streams, the perennial pools and the terrestrial systems, respectively. This ternary plot assists the classification of the regime of any stream that takes into account the statistics of the main proxies of the occurrence of aquatic habitats. The TREHS software also provides a classification of the regimes in the ternary plot that groups the regimes of assumed ecological significance and uses terms that are conflict-free from the current classifications. Furthermore, TREHS users can easily define new regime classes in this plot according to the ecohydrological characteristics of their streams.</p>


2015 ◽  
Vol 54 ◽  
pp. 137-152 ◽  
Author(s):  
Pierre-Alexandre Rastorgueff ◽  
Denise Bellan-Santini ◽  
Carlo Nike Bianchi ◽  
Simona Bussotti ◽  
Pierre Chevaldonné ◽  
...  
Keyword(s):  

2017 ◽  
Vol 29 (0) ◽  
Author(s):  
Rafela Neves Marreto ◽  
Maria da Graça Zepka Baumgarten ◽  
Mônica Wallner-Kersanach

Abstract: Aim This study aimed to evaluate the Trophic State Index (TSI) at the margin and in the channel of the Patos Lagoon estuary, considering different hydrological conditions. Methods Surface and bottom water samples were collected in three sites in the channel (margin and center) and in two sites at the Saco da Mangueira in different hydrological conditions in 2011. Results Waters at the Saco da Mangueira are very contaminated by phosphate and nitrogenous compounds. The TSI classifies these waters as being hypereutrophic, the consequence of both the release of effluents which were poorly treated and the low water flow in the inlet. Contamination was mild at the margins of the channel, where waters were classified as being eutrophic and mesotrophic. Trophic balance (mesotrophic waters - oligotrophic surface - bottom) was found in the center of the channel as a consequence of strong water flow and dilution of contaminants coming from the margins. Conclusions Spatial variation in the TSI value enabled clear distinction to be observed between the areas at the margins and in the channel, because it reflected the punctual presence of anthropogenic input in the marginal waters, mainly in the Saco da Mangueira. Effluent treatment must be required in order to control severe trophic imbalance in the waters at the margins of the city. Variations of the proposed index are a useful tool to identify sources of phosphate compounds in other aquatic environments.


2021 ◽  
pp. 67-98
Author(s):  
Daniele Tubino P. de Souza ◽  
Edson Grandisoli ◽  
Pedro Roberto Jacobi ◽  
Arjen E. J. Wals

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Lieza Corsita ◽  
Arwin Arwin ◽  
Barti Setiani Muntalif ◽  
Indah Rachmatiah Salami

Physico-chemistry and biological data were investigated  from  October 2010 until April 2011 of Jatiluhur reservoir. A total of six sampling stations were selected for this study. The discharge and hidrological data were obtained from Perum Jasa Tirta II Jatiluhur. The results showed that the hydrological regime in the reservoir Jatiluhur was affected by global phenomenon La Nina events in 2010 and early in 2011. Stream flows were determined during sampling to range from 78  to 482.5 m3/s. The water quality findings were as follows: pH (6.93-8.81), temperature (26.37-30.6°C), dissolved oxygen (0.733-5.2 mg/l), conductivity (2.45-233µmhos/cm), COD (7.36-96.9 mg/l), turbidity (4.063-65.6 NTU), total phosphate (0.002-0.324 mg/l), total nitrogen (0.99-5.96 mg/l), chlorophyl (2.237-43.37 mg/m3), visibility (30-160 cm). The eutrophication was pronounced at Jatiluhur reservoir. Canonical Correspendence Analysis found that some water quality parameters correlated positively with the discharge and the water level.


2021 ◽  
Vol 932 (1) ◽  
pp. 012011
Author(s):  
Y Wang

Abstract The Shiyang River basin is a typical inland arid region and one of the most fragile and sensitive areas of terrestrial ecosystems in China, and it is important to understand its ecological changes in a timely and accurate manner. This article selects the Shiyang River basin forest as the research area and uses Google Earth Engine (GEE) to evaluate and monitor the ecological environment quality of the Shiyang River basin from 1990 to 2020. The geographical detector model (GDM) was also used to analyse the sensitivity of the forest ecological environment to three natural factors: elevation, temperature and altitude. The results showed that the ecological quality of the natural forest is significantly better than that of the man-made forest area, and the ecological quality grade is higher. The forest change area RSEI has a large annual variation in ecological quality and is vulnerable to external factors. Among the influencing natural factors, the sensitive factors of precipitation and altitude are both greater than 84%. The temperature sensitivity of natural forests is stronger than that of man-made forests, ranging from 66% to 92% overall.


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